The present invention relates to an eddy current brake and the cooling thereof by means of a cooling medium.
Eddy current brakes are used to test power plants whereby the energy developed by the power plant is converted, by means of eddy currents, into heat within the brake system. As a result of the eddy currents, the total brake system is heated and care must be taken to remove the heat.
Heretofore proposed eddy current brakes have the general disadvantage in that their application is somewhat limited in those cases where continuous high loads are applied. These limitations occur because it is extremely difficult or impossible to remove the heat that is developed. Because of poor heat transfer which results from the shape of the cooling passages and also from the predominant flow velocities within the cooling passages, the temperature differentials between the inner housing wall of the brake on the side of the rotor and the outer wall are so high that plastic deformations occur of the components carrying the cooling fluid. This may cause seizure of the eddy current brake. Also, the elevated temperatures that result from deformation may, after some time, affect the bearings and may exceed tolerable temperature levels. As a result of repeated plastic deformations at relatively high loads, cracks develop after relatively short service time. This causes cooling fluid to enter into the inner chamber of the machine, rendering it useless.